The cost to install a tankless hot water heater can vary, depending on the type of gas pipes and electrical outlets in the home. For homes that do not require additional gas pipes and outlets, the price is approximately $100 to $200, according to CostHelper.
For most homes that do not have the electrical outlets, larger pipes and stainless steel ventilation system required for the tankless hot water heater, installation costs range from $1,800 to $2,000. Because tankless hot water heaters only supply hot water on demand, they can save money, according to the Department of Energy. Unlike tankless hot water heaters, most hot water heaters have a storage unit that fills regularly. The storage unit uses energy to fill it randomly.